This project emphasizes 3 approaches related to the structure and function of messenger-RNAs. First, the project attempts to define the nucleotide sequence at and around the site(s) of initiation translation of various messenger-RNAs in order to define features of messenger-RNAs that govern the initiation of protein biosynthesis. Second, the project attempts to define features of the RNAs of single stranded RNA viruses that govern the specificity of these RNAs during viral RNA replication. Third, the project attempts to develop and apply new methods for RNA nucleotide sequence analysis.